This invention relates to the field of microscopic examination of objects, one important example of which is leukocyte differential counts, i.e., the identifying and counting of the different types of white blood cells as well as red blood cell morphology studies. Since the task of finding or locating the desired blood cells on the slide is time consuming and tedious, there has been considerable effort expended previously in the area of automatically searching for and finding blood cells. One such reference is the Smithline U.S. Pat. No. 3,315,229, and there are other patents disclosing various details of automated blood study, for example, the Preston, Jr. et al U.S. Pat. No. 3,503,684, and Amos U.S. Pat. No. 3,806,257, and the Adkins U.S. Pat. No. 3,864,564.